BOSTON -- As soon as Mookie Betts made contact with the 13th pitch of his at-bat against J.A. Happ in the fourth inning Thursday night, he was one of at least 37,182 at Fenway Park who knew he was witnessing something special.

Betts, who rarely shows emotion on the field, immediately flipped his bat after hitting a grand slam to give the Red Sox a 5-2 lead. He pounded his chest, screamed into the dugout and even almost fell over as he approached first base.

"I almost went down," Betts said. "I had to depend on my athletic ability and it came through that time."

Betts went down 1-2 before fouling off six straight pitches from Happ. Two balls in the dirt and another foul later, Betts sent a low fastball over the Green Monster in what has been one of Fenway's most electrifying moments all year.

"We were like guessing pitches," manager Alex Cora said. "I told Roenicke, I said 'changeup here.' He said 'fastball up.' We both were wrong."

Betts' home run was the culmination of a long inning for the Red Sox, who caught two breaks in the fourth. An overturned call on a Xander Bogaerts slide into second base on a groundout extended the inning before Justin Smoak dropped a pop fly in foul territory that would have ended Betts' at-bat.

"The at-bat, the inning, with how the whole inning was going," Betts said," everybody was kind of waiting for something to happen. Like I said, he was tough. We just kind of showed how we battle."

At about the 10th or 11th pitch of the battle, the Fenway faithful began to stand and clap, recognizing Betts' superb at-bat. Betts himself deemed it a success after seven or eight pitches, telling himself that he had already worked Happ's pitch count enough to give the Red Sox a chance to do damage after a slow offensive night to that point.

Betts said that the at-bat was the most satisfying of his major-league career.

"I don't think so," Betts said when asked if he could remember an at-bat he was more proud of in his career. "Not one that ended in a way like that. I've had some long at-bats but they ended in weak contact or a strikeout. That's probably my favorite so far."

Betts' slam supported a strong bounce-back performance from starter David Price, who settled down after a first-inning homer and went 6.2 innings for the Red Sox, allowing just three earned runs and striking out eight Blue Jays. Price, who is in his third year with the Sox, had a hard time thinking of a time Fenway has been as electric as it was Tuesday during his tenure.

"[For something] that wasn't a walk-off or anything of that nature, probably. Yeah," Price said. "It was a very big moment. That's the most excited I've seen Mookie on the baseball field. This and his home run in Milwaukee. I say it to him all the time, I want to see that emotion again from Milwaukee. I'm happy it came on my day the way that it did today. It was a good win for us."

Price was referencing an eighth-inning homer Betts hit against the Brewers last May to give the Red Sox an eventual 4-1 win at Miller Park. While Betts was fired up for that one, it couldn't match the feeling of his grand slam Thursday.

"Since I've been in the big leagues, it's probably the most excited I've been," Betts said.

Betts' excitement spread to the crowd, which has been louder in the last few days than it has been all year. With the Red Sox winning their season-high 10th consecutive game, fans are starting to sense that this team could be special.

"It was loud here," Cora said. "In that at-bat, it was cool to see the fans standing up. As soon as he hit that ball, the place went crazy. I think the city is starting to like this team."